Ingot mold plug



Oct. 10, 1939. H. K. Rl GD ON INGOT MOLD PLUG 2 Sheets-Sheet 1 Filed May 25, 1939 INVENTOR. HQWARD K. 121 DON BY w.m k\ 1w ATTORNEYJ'.

I Oct. 10,1939. H. RIGDON 15 INGOT MOLD PLUG Filed lay 25, 1939 2 Sheets-Sheet 2- F1G.1Z.

INVENI'OR. HOWARD K.RI.G'DON ATTORNEY J.

Patented Oct. 10, 1939 PATENT OFFICE INGOT MOLD PLUG Howard K. Rigdon, Painesvillc, Ohio Application May 25, 1939, Serial No; 275,584

9 Claims.

This is a continuation in part of application Serial No. 226,053, filed August 22, 1938.

The invention pertains to improvements in plugs for closing the bottom openings of ingot B molds of the big-end-up variety commonly used for casting steel ingots.

Plugs for this purpose are ordinarily good for only one pouring. Consequently, cost is an im-' portant item. Heretofore, relatively inexpensive l plugs of refractory material have been used, but

these have proven to be unsatisfactory because of breakage, and more particularly because particles of the material frequently rise within the molten metal of the ingot and produce so-called inclusions", resulting in blow holes or weak spots when the ingot is subsequently rolled into steel- 5 tedious of handling, especially in cases where the elements are disconnected.

It is the fundamental purpose of the invention to produce a cheap yet highly satisfactory mold plug in the nature of a relatively thin metal shell comprising a top wall that is desirably, though not necessarily, flat and circular, and a peripheral wall that depends from the edge of the top wall and converges downwardly, the same pref-,

erably being generally frusto-conical, and having the same taper and contour as the wall of the mold opening wherewith it is intended for contact, and being of a size to fit said opening. It is also desirable that the plug, and more especially the peripheral wall thereof, be slightly yieldable. To the attainment of these ends, the

plug is preferably die stamped or drawn or otherwise formed from a single piece of heavy sheet metal or metal plate; and, as will be appreciated by those familiar with this class of work, accuracy of size, taper and contour of the peripheral wall is assured in a plug produced by such a method. The yielding character of the plug enables it to be tamped firmly into the bottom opening of the mold and thereby placed under tension so as to cause the plug to securely hold its positionwithin the opening against displacement by impingement thereon of the molten metal at the beginning of the pouring operation, and this quality and action of the plug also insures efiective closing or sealing of the opening thereby to obviate the formation of fins about the plug that result from the use of ill fitting plugs or closures.

It is an additional object of the present invention to further cheapen and improve a plug of the above described character by forming it from a square or polygonal blank 'so that the finished product will be characterized by a peripheral portion that is relativelydeep where the corners of the blank occur. This design or construction effects avsaving in material over forming the plug 10 from circular blanks, and at the same time increases the yielding character or resiliency of the peripheral portion, it eing obvious that the relatively deep parts wil yield more readily than a continuous frusto-conical wall of substantially the same vertical dimension throughout its circumference.

In broader terms, the present invention cohtemplates the production of a mold plug having a top wall against which the molten metal is adapt- 50 ed to impingeduring the pouring operation, and a peripheral portion comprising yielding downward extensions spaced apart about the circumference of the plug.

In the accompanying drawings that form a part hereof, and wherein like reference characters designate corresponding parts throughout the several views, Fig. 1 is a top plan view, Fig.2 a side elevation partly in section, and Fig. 3 a bottom plan view of one form of my improved mold v3o plug; Fig. 4 is a central vertical section through the lower portion of an ingot mold and ingot of the big-end-up type showing the bottom opening of the mold closed by the form of the invention illustrated lnthe preceding views; Fig. 5 is a central vertical, section through a modified form of the invention with the adjacent parts of a mold indicated in broken lines; Fig. 6 is a central vertical section through a plug that differs from the form illustrated in Figs. 1 to 4 by the top wall being dished or depressed and by the inclusion of a filler; Fig. 7 is a top plan view of a 'plug that is formed from apolygonal or square blank, the original size and shape of the blank being indi cated by the dot-and-dash lines in said vi Fig. 8 is a bottom plan view of the same Figs. 9 and 10 are sections through mating, taken on the respective lines 9-9 and ill-40' of Fig. 8; Fig. 11 is a central vertical section'through the lower portion of an ingot mold with. the present form of the plug closing the bottom opening thereof, the plug, in this instance, being, reinforced by a filler; and Fig. 12 isa central'vertical section through the polygonalsblank type of plug with the top wall dished or depressed and reinforced or fortified by a filler.

In Figs. 1 to 4, my improved plug is designated generally by the reference numeral I, and it comprises a top wall 2 and a peripheral wall 3 that depends from the edge of the former wall and converges downwardly. The plug is shown as circular in plan, although it might have other shapes depending upon the cross sectional shape of the opening of the mold wherewith it is intended for use. The plug consists of a relatively thin walled shell that is preferably drawn from heavy sheet metal or metal plate, a practical thickness for a plug of usual size being approximately one-quarter inch. In some metals a wall of lesser thickness would be practical, and among the materials suited to the purpose are iron, steel and copper, the latter having the advantage of a relatively high coeflicient of heat conductivity, causing a plug of such material to rapidly carry away the heat of the molten metal causing the ingot to quickly chill in the region of the 'plug.

-Furthermore, the molten metal would not weld to copper as would be the case with either iron or steel.

In Fig. 4, the plug I is shown as tightly fitting within the upper end of the bottom opening 0 of a mold M and as being contacted by the bottom of an ingot I. As is well known to those skilled in the art, the purpose of the opening 0 is to permit a stripping device or plunger to be inserted upwardly through the mold for the purpose of dislodgin'g the ingot I therefrom. During the stripping operation, the mold may be supported upon the customary stool which has an opening registering with the opening 0 of the mold for the accommodation of the stripping device, or the mold may be supported in any other suitable way that aifords access of the stripping device to the opening 0.

It will be observed that the peripheral wall 3 of the plug i,has a taper corresponding to that of the wall of the opening 0, and it is sized to fit said opening as accurately as practically possible. When the plug is dropped into the opening with the slightest degree of care it will properly position itself within the opening, but in order to insure sealing of the opening it is desirable that the plug be tamped into the opening of the mold, its yielding character insuring a tight fit between the peripheral wall of the plug and the wall of the opening and causing the plug to securely retain its position during the pouring operation.

As previously mentioned, the plug, when made of certain metals, such as steel and iron, will become welded to the ingot, in which event it is disposed of during the usual slabblng oiI of the butt crop of the bloom.

Fig. 5 shows a modified form of the invention, designated l0, wherein the peripheral wall I; ex-. tends rather abruptly inwardly beneath the edge of the top wall l2 and thence, with an initial curve, downwardly in slightly convergent relation to the axis of the plug to efiect a-contour and taper corresponding to that of the wall of the opening 0. In the present instance, the plug is made to fit not only the conical portion of the wall of the opening but to conform in contour with the outwardly flaring curved portion through which the conical wall merges into the curved bottom wall of the mold cavity.

According to the form of the invention illustrated in Fig. 6, the top wall l5 of the plug it is slightly dished or depressed, and a filler I1 is confined within the downwardly convergent peplug throughout the region occupied by the illler.

The filler reinforces or fortifies the plug, and may permit the use of a thinner gauge metal sheet or plate without danger of the plug collapsing under the weight and heat of the molten ingot metal.

As illustrative of that modification of my invention involving a polygonal blank from which the plus is formed, I have shown in Figs. 7 to 12 a plug that is drawn or formed from a square blank, the original size and shape of which is indicated by the dot-and-dash lines in Fig. 7. Obviously, the blank might be of other shapes, as triangular for example. The plug of Figs. 7 to 11 is designated generally by the reference numeral 20, and it has a relatively flat circular top wall 2| and a peripheral wall 22, from which depend the pointed extensions or prongs 23 that are formed by the corner portions of the blank. A filler 24' is shown as occupying the interior of the plug in F18. 11.

In this form of the invention, whether the flller 24 is included or not, the plug finds its approximate seat when dropped into the tapered opening 0 of the mold M, and when tamped into the opening the extended points or prongs ot the peripheral wall are forced inwardly under tension so as to cause the plug to better hold its position within the opening, it being understood that when the plug is'm'ade, the downward convergence of the prongs is desirably very slightly less than that of the opening.

- Fig. 12 shows a plug 25 in which the circular top wall 26 is slightly dished or depressed, and as having confined within the peripheral portion 21 a filler 28 which, as is the case with either 'of the previously mentioned fillers II or 24, may

be of wood, or of any other suitable material, includingthose enumerated in the description of the form shown in Fig. 6.

Where the term sheet metal is employed in the claims-it is intended to include what'is ordinarily referred to in the trade as metal plate";

in other words, it designates metal sheet and inetal plate of such thicknesses as are applicable to my purpose.

Having thus described my invention, what I claim is:

1. A plug for the downwardly convergent bottorn opening of an ingot mold, said plug being formed from a single piece of sheet metal of substantially the same thickness throughout and comprising a top wall against which the molten metal is adapted to impinge during the pouring of an ingot, and a peripheral wall depending directly and abruptly from the edge of the top wall and having a downward convergence corresponding substantially to that of said bottom opening whereby the plug finds its seat when dropped or tamped into the opening and closes the opening in approximately the plane of said top wall.

2. A plug for the downwardly convergent bottom opening 'of an ingot mold, said plug being formed from a single piece of sheet metal of substantially the same thickness throughout and comprising a top wall against which the molten rectly and abruptly from the edge of the top wall and having a downward convergence corresponding substantially to that of said bottom opening whereby the plug finds its seat when dropped or tamped into the opening and closes theopening in approximately the plane of said top, and a reinforcement within the plug sustained by the peripheral wall thereof.

3. A plug for the tapered bottom opening of an ingot mold formed in the shape of an inverted cup from a single piece of sheet metal and comprising a flat top wall against which the molten metal is adapted to impinge and a peripheral wall that is slightly yielding due to the inherent flexibility of the sheet metal, said peripheral ,wall depending from the edge of the top wall and converging downwardly and having a taper corresponding substantially to that of the bottom opening of the mold whereby the plug finds its seat when dropped or tamped into the opening and effectively seals the opening in approximately the plane of said top wall.

4. A plug for the circular tapered bottom opening of an ingot mold formed in the shape of an inverted cup from a single piece of sheet metal I and comprising a circular top wall against which the molten metal is adapted to impinge, and a downwardly convergent frusto-conical peripheral wall depending abruptly from the edge of the top wall and conforming substantially to the convergence of the bottom opening and being adapted to find its seat therein and to be placed under compression when the'plug is tamped into said opening due to the inherent resiliency of the sheet metal, theplug thus'serving to close the opening in approximately the plane of said top wall.

5. ,A plug forthe downwardly convergent bottom opening of an ingot mold, said plug being formed from a single piece of sheet metal and consisting of a top wall against which the molten metal is adapted to impinge during the pouring of an ingot, and a peripheral portion comprising a plurality of separated and downwardly extended portions spaced apart circumferentially of the top wall and having a downward convergence corresponding substantially to that of said bottom opening whereby the plug flnds its seat when dropped or tamped into the opening and closes the same in approximately the plane of said top wall.

6. A plug for the downwardly convergent bottom opening of aningot mold, said plug being formed from a polygonal blank of sheet metal and comprising a top wall against which the molten metal is adapted to impinge during the pouring of the ingot and a peripheral portion depending directly and abruptly from'the edge of the top wall and having a downward convergence corresponding substantially to that of said bottom opening, the corners of the blank defining circumferentially spaced downwardly extending parts. I

7. A plug for the downwardly convergent bottom opening of an ingot mold, said plug being formed from a square blank of sheet metal and comprising a circular top wall against which the molten metal is adapted to impinge during the pouring of an ingot, and a peripheral wall depending directly and abruptly from the edge of the top wall and having a downwardconvergence corresponding substantially to that of said bottom opening, the corners of the'blank forming circumferentially spaced downwardly extended points. I

8. A plug for the downwardly convergent bottom opening of an ingot mold, said plug being formed from a polygonal blank of sheet metal and comprising a top wall against which the molten metal is adapted to impinge during the pouring of an ingot, and a peripheral portion depending directly and abruptly from the edge of the top wall and having a downward converg'ence corresponding substantially to that of said bottom opening, and a reinforcement confined within the plug by the downwardly convergent surrounding portion thereof.

9. 'A plug for the downwardly convergent bottom opening of an ingot mold, said plug being formed from a square blank of sheet metal and comprising a circular top wall against which the molten metal is adapted to impinge during the pouring of an ingot, and a peripheral wall de-- HOWARD K. RIGDON. 

